Are there any fundamental differences to use numpy.zeros or zeros?

I have downloaded the python 2.6 and installed numpy-1.6.1-win32-superpack-python2.6 and scipy-0.9.0-win32-superpack-python2.6. It is running on a Window with window 2000 professional as OS.

However, when I run python, with the following commands, following error message appear, could you mind to teach me how to solve it?

>>> x =开发者_高级运维 zeros([K], int32)

Traceback (most recent call last):
file "<stdin>", line 1, in <module>
NameError: name 'zeros' is not defined.

I then tried to import numpy:

>>> import numpy
>>> x=numpy.zeros([K], int32)
Traceback (most recent call last):
file "<stdin>", line 1, in <module>
NameError: name 'K' is not defined.

Are there any fundamental differences to use numpy.zeros or zeros? What is the difference between them?

I also tried to readin a series of files (saved in the same directory) to get python doing analysis for me. I learnt from the manual that I should use

f=open('C:/xxx.txt', 'w') # for single file

How to apply this to a series of files?

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The error message says it all: You're using a name that hasn't been defined yet.

If you import numpy, and numpy contains a zeros() function, then you must call it as numpy.zeros(). If you want to refer to zeros() directly, you can from numpy import zeros.

If you pass the variable K to a function, K must have been assigned to something before. What is K supposed to be in your example?

As for opening files, I don't think the manual says that. At least, it should be f = open(r'C:\xxx.txt', 'w').

To open more than one in a loop, you can

for filename in filelist:
    with open(filename, 'w') as outfile:
        # do something.
        # The with block ensures that the file will be closed after use

Also check out the glob module and os.walk().

All this is covered pretty well in the Python tutorial.

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Question 1

Your problem is not with numpy, it is simply that you have not defined K.

Question 2

One simple way to enumerate files in a directory is glob.

from glob import glob
for filename in glob('*.txt'):
    print filename

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You need to read Python Tutorial to get your answers. The first code sample doesn't work because you didn't import zeros. The second - because you don't have K variable.